Many types of respirators are available for different uses, such as air filtration, or for providing clean air or breathing gases at positive supply pressure to persons in hazardous breathing environments, such as firefighters and soldiers, or for cleanroom workers, medical patients, sleep apnea sufferers, etc. Many such respirators include a flexible mask portion that engages and at least partially conforms to portions of a wearer's face, surrounding the nose and/or mouth. The mask portion is typically made at least partially from a flexible rubber or rubber-like material, such as silicone.